Technical Field
The present disclosure relates to a medical instrument to be used for supplying a fluid into a living body.
Background Art
The paranasal sinus, as a living body organ, is an intraosseous cavity adjacent to the nasal cavity, and communicates with the nasal cavity through an aperture called the natural ostium. Normally, secretion, bacteria and the like in the paranasal sinus are discharged through the natural ostium to the nasal cavity. When swelling of mucous membrane in the nasal cavity is generated by common cold-induced rhinitis, allergic rhinitis or the like or when the nasal cavity is narrowed due to septum deviation, hypertrophic rhinitis or the like, however, the natural ostium is stenosed, leading to chronic inflammation inside the paranasal sinus. Such a disease is called sinusitis.
As a treatment of sinusitis, conventionally, there has commonly been practiced a surgical treatment in which the stenosed part of the natural ostium is removed by use of forceps, a drill or the like. In recent years, on the other hand, attention has been paid to a minimally invasive treatment in which the narrowed natural ostium is dilated by a balloon catheter. For example, JP-T-2009-500051 discloses a dilating method in which a balloon catheter is operated under endoscopic observation to positionally match the balloon to the natural ostium, and the stenosed part is dilated thereby. In this method use is made of a catheter device that is provided with a predetermined lumen and that makes it possible to supply a variety of fluids to the inside of the nose and to suck out mucus, body fluid and the like present inside the nose. Since such liquids as mucus and body fluid are present in comparatively large amounts in the inside of the nose, for example, in the nasal cavity, these liquids may hamper the procedure. In addition, the liquid such as pus present in the paranasal sinus needs to be removed to the outside of the living body after the dilation of the stenosed part. By use of the aforementioned catheter device, therefore, the treatment of sinusitis can be carried out efficiently. In the case of supplying a fluid by use of the conventional catheter device, the fluid supplied into the lumen is discharged through an aperture provided at the distal end of the lumen.
In the treatment of sinusitis, it may be desired to introduce a catheter device up to the depth of the paranasal sinus for the purpose of cleaning the inside of the paranasal sinus. When a distal portion of the catheter device is formed to be longer, for instance, the distal portion of a catheter can be guided farther into a living body. The elongation of the distal portion, however, worsens the operability of the catheter main body, possibly making it bothersome to introduce the catheter into the living body. Another method may be contemplated in which a fluid tube is separately inserted in a lumen of a catheter device, and the tube is led out from the distal end of the catheter device. In this method, however, the insertion of the tube in the lumen makes it impossible to introduce other medical instruments. Consequently, an operation of replacing the tube with a treatment instrument is needed at the time of using the treatment instrument, which makes the procedure bothersome.